| The pertinent variable in this form of meiotic drive is the presence of differing numbers of centromeres on paired homologous chromosomes. |
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| They treated bivalent and multivalent pairings as two totally different meiotic processes. |
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| Subsequently, one of the two mating-type alleles was lost during mitotic or meiotic divisions. |
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| During the first meiotic division, homologous chromosomes pair and segregate into two cells. |
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| Therefore, progression from mitosis into meiotic prophase is spatially organized in a linear fashion extending from the distal end. |
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| Facultative amphimixis is the equivalent of the mechanism described under meiotic parthenogenesis. |
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| The proteins encoded by these genes are thought to participate in the biochemical steps that lead to meiotic recombination. |
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| Using cytologically tagged chromosomes, we established a role for the microtubule motor dynein in meiotic chromosome segregation. |
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| Several models have been proposed to explain the mechanism responsible for meiotic recombination. |
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| The absence of chiasmata can readily account for the observed defect in meiotic chromosome segregation. |
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| At this time, the primary oocyte's first meiotic division occurs, resulting in the formation of the first polar body and the secondary oocyte. |
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| This interaction is thought to be necessary for the proper pairing and segregation of homologous chromosomes during the first meiotic division. |
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| Three properties of meiotic chromosomes act to form a bivalent that will undergo proper reductional division. |
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| During meiotic prophase in females, chromosomes condense and pair to form bivalents. |
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| Restoration of the diploid stage is often strictly controlled and brings together products separated at the first meiotic division. |
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| For the treatment with colchicine, a prolongation of the duration of the meiotic divisions was observed. |
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| The synaptonemal complex is present at this stage, and meiotic recombination is completed within this context. |
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| If the arrest is dependent upon recombination, then preventing recombination should suppress the meiotic progression defect. |
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| Metaphase spindles with replicated mitotic chromosomes were assembled in meiotic Xenopus egg extracts as described. |
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| The origin of the extra chromosome 21 due to meiotic non-disjunction was 79.24 per cent maternal and 20.76 per cent paternal. |
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| In these mutants, the meiotic products remain in interphase in unfertilized eggs and undergo inappropriate DNA replication. |
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| Regions of the germline with cells in mitosis or different stages of meiotic prophase are indicated. |
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| High fidelity of meiotic chromosome segregation is essential for the propagation of all sexually reproducing organisms. |
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| Males can, therefore, arise spontaneously, as a result of the rare meiotic loss of an X chromosome. |
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| Thus, whereas the parental species reproduce sexually, the hybrid reproduces unisexually due to the result of meiotic drive, but still depends on a sexual hang-up. |
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| Lying between, and nurtured by, the Sertoli cells, the primary spermatocytes undergo two meiotic divisions and cellular remodelling to produce mature sperm. |
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| Since Spo11 is present throughout eukarya, we plan to apply this method to study meiotic homologous recombination in other species too. |
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| There may be specific types of mutagens, e.g. aneuploidy inducers, which act preferentially during meiotic gametogenesis stages. |
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| Temporary heat stress near the time of estrus and ovulation can reduce oocyte quality by altering meiotic processes, directly affecting conceptus quality and survival. |
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| The authors subsequently investigated the impact of short-term bisphenol A exposure on meiotic processes during oogenesis. |
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| After meiosis, the four meiotic products undergo an additional mitotic division to yield eight haploid nuclei, which differentiate into an octad of eight ascospores. |
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| However, individuals who are heterozygous for inversions produce aberrant meiotic products along with normal products. |
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| The factors controlling formation of meiotic double-strand breaks are not well known. |
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| New combination of hereditary traits and reduction of the number of chromosomes are the aim of meiotic division. |
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| In germinal lineages, replicative insertions are frequent, occurring in premeiotic, meiotic, and postmeiotic cells, while excision events are rare. |
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| Meiotic spindle poles of mutant embryos are not as well focused as wild type, and meiotic failure often leads to multiple maternal pronuclei as compared to wild type. |
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| In wild-type hermaphrodites, germ cells at the dorsoventral flexure exit the pachytene stage of the first meiotic prophase and proceed to diakinesis. |
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| This caused Chance and Schoener to resort to a meiotic telephase of the arachnoid sperm in which a mitochondrial aggregate or ''nebenkern'' was formed in meiotic telephase. |
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| This view is consistent with the general findings that mitotic recombination events, contrary to meiotic events, are mainly unassociated with crossing over. |
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| Thus, both tagged proteins could support initiation of meiotic recombination at a temperature commonly used for sporulation of laboratory strains. |
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| Preliminary meiotic analysis of the F 1 hybrid showed the occasional formation of an anaphase I bridge between two large chromosomes, as is typical for paracentric inversions. |
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| The early gene family encodes factors required for meiotic DNA replication, chromosome pairing, synaptonemal complex formation, and meiotic recombination. |
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| Additional information from treated spermatogonial stem cells can be obtained by meiotic chromosome anaylsis for chromosome-type aberrations at diakinesis-metaphase I when the treated cells become spermatocytes. |
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| Assembled germlines show areas of reduced nuclear density, intermixed meiotic stages, and unequally spaced diakinetic nuclei. |
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| In various coleopterans the mitotic and meiotic activities of the larval, pupal and imaginal stages occur diversely. |
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| As a result, the mature eggs produced subsequent to the two meiotic divisions have the same ploidy as the somatic cells of the female salamander. |
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| Repair of these double-strand breaks leads to crossover exchanges between non-sister chromatids and thus ensures segregation of the recombined chromosomes at the first meiotic division. |
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| Our model organism is the budding yeast Saccharomyces cerevisiae, which is among the closest to Mammals in terms of meiotic recombination mechanisms, and which allows a large panel of molecular and genetic approaches. |
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| Furthermore, as they mature, gametes undergo meiotic reduction. |
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| Each meiotic division results in a tetrad of two small spores that produce male gametophytes and two larger spores that produce female gametophytes. |
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| It has been established that, cumulus cells have an important role in oocyte meiotic transition from prophase to metaphase. |
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| Aneuploidy: A chromosome number that is not an exact multiple of 23, usually resulting from a meiotic non-disjunction error in the production of gametes. |
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| Pre-meiotic bands and novel meiotic spindle ontogeny in quadrilobed sporocytes of leafy liverworts. |
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| During development, some of the potentially spore-bearing tissue is used as nutrient by the sporocytes as they complete the meiotic divisions that result in colourless kidney-shaped spores. |
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| During the second meiotic division the chromatids separate. |
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| These meiotic division processes involve extensive rearrangement of microtubules and microfilaments. |
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| Mammalian spermatogenesis occurs continuously with individual maturation of sperm through meiotic division of spermatocytes. |
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| The oocyte of Rana pipiens, whilst in the process of meiotic division, is pricked with a fine glass needle, the effect of which is to provoke activation. |
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| To study meiotic abnormalities in men with nonobstructive azoospermia. |
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| Early in meiotic recombination, Spo11, a meiosis-specific endonuclease, induces the DNA double-strand breaks that initiate exchange of genetic material between the homologous chromosomes. |
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| This localization suggests that meiotic recombination is initiated in leptotene with the cooperation of these two proteins and remains in zygotene. |
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| Advancement of meiotic resumption in Graafian follicle by LH in relation to preovulatory ageing of rat oocytes. |
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| The male gametophyte phase of the life cycle begins in the microsporangium with meiotic production of tetrads of microspores followed by the division of each haploid microspore into a three-celled pollen grain. |
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| In most organisms, including humans, chiasmata are seen in the meiotic chromosomes in both sexes, and observations on hybrid progenies show that recombination of linked genes occurs also in both sexes. |
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| This involved, in what was at the time only a hypothesis, eliminating any element of chance, as the embryo would develop based on the genetic heritage of the diploid adult cell without meiotic change or gamete fusion. |
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| Cyclic AMP and meiotic arrest in mammalian oocytes. |
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| Damage of oocytes quality during warmer periods, leading to meiotic arrest of oocytes at anaphase and telophase stages, could be provoked by several factors. |
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| Ultrastructure of meiotic kinetochores investigated by electron microscopy revealed that bivalents in metaphase I have defined kinetochore region for each chromatid. |
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| More than 30 sporangial meiotic cells at late diplotene were counted. |
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| It has been shown that in the process of oocyte maturation, meiotic resumption is associated with the loss of gap junctions between the oocyte and the granulosa cells. |
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| The materials from five Japanese populations had 36 chromosomes in the meiotic cells, and 64 spores per sporangium, which suggested that these species are sexual diploids. |
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